The CALGB Leukemia Tissue Bank (LTB) serves as a centralized tissue bank of blood and bone marrow specimens procured from patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), myelodysplastic syndrome (MDS), chronic myelogenous leukemia (CML), chronic lymphocytic leukemia (CLL) and other hematologic malignancies enrolled on CALGB treatment protocols. The specific aims of this proposal will be accomplished through CALGB protocol 9665, a protocol for the procurement of relevant tissue specimens. The associated work will be performed in the laboratory of Michael Caligiuri, M.D. at The Ohio State University.